What does "Too many DNS lookups'" mean?

The SPF record for a domain specifies which IP addresses are allowed to send an email on behalf of that domain. When an email is received, the receiving server checks the SPF record to verify that the email is coming from a valid source. However, there is a limit of 10 DNS lookups that can be performed during this process. If a domain's SPF record contains more than ten lookups, it means that the entries after the 10th lookup will not be checked, and the email may be delivered even if it is not from a valid source. This is known as "too many DNS lookups" in SPF. EasyDMARC solves this problem with the EasySPF solution.